1. Field of the Invention
This invention relates to amorphous metal alloys and, more particularly, to amorphous metal alloys containing iron, chromium, carbon and phosphorus combined, optionally, with minor amounts of copper, molybdenum, tungsten, boron and silicon. The amorphous metal alloys of the invention are strong, ductile and resistant to corrosion, stress corrosion and thermal embrittlement.
2. Description of the Prior Art
Novel amorphous metal alloys have been disclosed and claimed by H. S. Chen and D. E. Polk in U.S. Pat. No. 3,856,513, issued Dec. 24, 1974. These amorphous alloys have the formula M.sub.a Y.sub.b Z.sub.c, where M is at least one metal selected from the group consisting of iron, nickel, cobalt, chromium and vanadium, Y is at least one element selected from the group consisting of phosphorus, boron and carbon, Z is at least one element selected from the group consisting of aluminum, antimony, beryllium, germanium, indium, tin and silicon, "a" ranges from about 60 to 90 atom percent, "b" ranges from about 10 to 30 atom percent and "c" ranges from about 0.1 to 15 atom percent. Also disclosed and claimed by the aforesaid patent to Chen et al. are amorphous alloys in wire form having the formula T.sub.i X.sub.j, where T is at least one transition metal, X is at least one element selected from the group consisting of aluminum, antimony, beryllium, boron, germanium, carbon, indium, phosphorus, silicon and tin, "i" ranges from about 70 to 87 atom percent and "j" ranges from about 13 to 30 atom percent.
More recently, iron-chromium base amorphous metal alloys have been disclosed by Masumoto et al. in U.S. Pat. No. 3,986,867. These alloys contain 1-40 atom percent chromium, 7-35 atom percent of at least one of the metalloids phosphorus, carbon and boron, balance iron and, optionally, also contain less than 40 atom percent of at least one of nickel and cobalt, less than 20 atom percent of at least one of molybdenum, zirconium, titanium and manganese, and less than 10 atom percent of at least one of vanadium, niobium, tungsten, tantalum and copper.
The alloys taught by the Chen et al. and Masumoto et al. patents evidence good mechanical properties as well as stress and corrosion resistance. Structural reinforcements used in tires, epoxies and concrete composites require improved mechanical properties, stress and corrosion resistance, and higher thermal stability. The improved properties required by these reinforcement applications have necessitated efforts to develop further specific alloy compositions. Amorphous metal alloys having improved mechanical, physical and thermal properties are taught by U.S. Pat. No. 4,067,732 and U.S. Pat. No. 4,137,075. Such alloys contain substantial quantities of scarce, strategic and valuable elements that are relatively expensive.